Portable unitary battery powered hand-held magnifying apparatus

Abstract

A portable unitary battery powered hand-held magnifying apparatus which is especially useful for examining gems includes a tubular battery casing with a penlight bulb mounted at its end to provide the necessary dark field illumination for showing inclusions in a gem. A ten power triplet type magnifying lens is hingedly mounted to the end of the tube for convenient carrying but when moved 90° its lens' axis is then perpendicular to the nominal light axis. The light bulb is in a parabolic reflector to provide substantially parallel rays. The focal distance of the lens is at the light axis where a gem would be placed for examination.

What is claimed: 
     
       1. A portable unitary battery powered hand-held magnifying apparatus where the eye of a viewer may observe a specimen comprising: a light source having substantially parallel rays centered around a light axis;   a viewing lens having an optical axis perpendicular to said light axis and a focal point substantially at said light axis when in an operating position;   means for holding and retaining said lens;   a tubular battery case for holding battery means to power said light source and also for retaining said light source and including actuating means for energizing said light source;   hinge means for connecting said lens holding means to said battery case for allowing said holding means to be folded down onto said battery case in a stowed position to form an essentially continuous tubular like structure;   said hinge means, when opened in said operating position, placing said optical axis perpendicular to said light axis, and offsetting said lens from said light source to prevent substantially all direct rays from the light source from entering said lens and the eye of said viewer whereby dark field illumination of said specimen which is placed at the intersection of the focal point of said lens and said light axis is accomplished to illuminate inclusions in said specimen.   
     
     
       2. Apparatus as in claim 1 where said light source is recessed in a parabolic reflector which serves as the termination of said tubular battery case to both shield the light source to prevent direct light rays from entering said lens and the eye of said viewer and also to provide said substantially parallel light rays. 
     
     
       3. An apparatus as in claim 1 where said lens is of the triplet type which has been corrected both for chromatic and spherical aberrations. 
     
     
       4. An apparatus as in claim 2 where said optical axis, in its operating position, is displaced from the end of said light reflector a sufficient distance to leave space for large specimens to be positioned at said focal point. 
     
     
       5. An apparatus as in claim 1 where said stowed position of said optical axis and said light axis coincide. 
     
     
       6. An apparatus as in claim 1 in which said battery case includes a cut-away insulating plastic sleeve slidable in said battery case carrying said light source which is in the form of a penlight bulb. 
     
     
       7. An apparatus as in claim 6 where said plastic sleeve includes a channel along its longitudinal periphery and where said means for actuating said light source includes pushbutton means having a hemispherical button extending through an aperture in the side of said battery case and a leaf spring having one end permanently attached to the spherical pushbutton and the other end permanently bent with the apex of the bend being biased against said channel and the other end of the spring making contact with the battery casing, said leaf spring being juxtaposed and spaced in its resting position from a conductive portion of said light bulb whereby pressing of the hemispherical button by the user allows the metal leaf spring to make contact with the conducting bulb portion and thus an electrical connection between the bulb and the battery casing to be completed to energize said light bulb. 
     
     
       8. An apparatus as in claim 1 where said hinge means includes detent means to detent said lens holding means both in its operating position and in its stowed position. 
     
     
       9. An apparatus as in claim 8 where said detent means includes a spring biased ball located in a channel in the movable portion of said hinge means and rounded out detents in the fixed portion of said hinge means at locations corresponding to said operating and stowed positions.